Stomachaches

I started the paleo diet a little over a month ago, no grains or dairy. I have been gluten free 4 years. I had a slip up mid way through the month of paleoness and got sick and realized I needed to get back on the diet. I have been solid paleo for 12 days. But I am now experiencing the stomachaches I used to get when I was not paleo. Also weird soft light colored stools but constipation like, little deer poops every couple hours. Should I eat some grains? I can't even exersize when I feel like this. I do feel like I am thinning up which is a good sign. Has anyone experienced this?